Mucolipidosis type IV (MLIV) is a rare autosomal recessive neurodegenerative disease caused by mutations of MCOLN1, which codes of mucolipin-1 a putative cation channel located in lysosomes. This research proposal aims to study the natural history of neurological and retinal manifestations of MLIV It also aims to increase awareness and improve diagnosis of MLIV among patients with cerebral palsy and those with retinal dystrophy of unknown cause. Over the past decade we have been studying prospectively various clinical and genetic aspects of MLIV in the only study of its kind. We hypothesize that MLIV is a combination of mostly developmental abnormality in the CMS and a degenerative retinal process. In this application we propose to 1) recruit known and newly diagnosed patients with MLIV and systematically study the neurological and retinal function over time. 2) Contact practicing physicians that take care of cerebral palsy patients and those with retinal dystrophy to increased awareness and improve diagnosis of MLIV. Based on our experience, we believe that many MLIV patients go undiagnosed. This project will help characterize and quantify the clinical abnormalities of MLIV and thus help define a patient population and outcome measures for future clinical trials.